复合改性膨润土固定尾矿中Zn的研究

Studies on immobilization of zinc in tailings by composite modified bentonite

以钠基膨润土(B)为原料,加入两种改性剂,采用湿法制得复合改性膨润土(MB),并用MB固定某锡矿尾矿中的Zn。采用扫描电镜(SEM)和X射线衍射分析仪(XRD)对改性前后的膨润土进行了表征,证实改性剂壳聚糖和乙二胺部分负载到膨润土表面,部分插层到膨润土层间。通过重金属浸出实验对MB固定尾矿中Zn的效果进行了研究,单因素实验结果表明,MB的固定效果要优于B,尾矿中Zn的浸出量降低57%~83%,且在酸度较大时也有良好的固定效果。其最佳固定条件为:MB投加量为1.5 g/50 g,反应温度为35℃,p H可以低至4.0,固定过程在4 h内达到稳定。正交实验结果表明,p H是控制MB固定尾矿中Zn的最重要的影响因素,其最佳的固定条件组合与单因素实验相吻合。

In this study,a new modified bentonite( MB) was prepared by solution method with the Na-base bentonite( B) as raw material and two different organic compounds as modifiers. The MB was used for the immobilization of zinc in tailings. The surface structure of original bentonite and modified bentonite was characterized by SEM and XRD,the results indicated that chitosan and ethanediamine were incorporated onto bentonite and intercalated into bentonite partially. The immobilization ability of MB was studied by leaching experiment,and MB showed better results than B,even in a relatively acidic environment. The immobilization rate of Zn in tailings was57% ~ 83%. The single factor experiment showed that the optimum immobilization conditions were: MB adding1. 5 g /50 g; reaction temperature of 35℃; p H≥4. 0; stable time≥4 h. The orthogonal experiment showed that p H was the most important condition,and other results were the same as the single factor experiments.